Preparation of Thin and Dense Lanthanum Cobaltite Coating on Porous Tubular Alumina Supports by Electrophoretic Deposition

Abstract

The electrophoretic deposition EPD process is one of several ceramic powder assembling technologies using a simultaneous colloidal process and electrochemical driving force. For the further development of the EPD technique, the possibility and the usefulness of preparing a thin and dense ceramic coating on non-electronically conductive porous tubular ceramics using the EPD technique was investigated. La 0.8 Sr 0.2 Co 0.8 Sr 0.2 O 3ࢬd LSCF was used as the deposition material and a porous alumina tube was used as the deposition substrate. Methanol MeOH was suitable as a dispersing medium for the LSCF powder. LSCF particles were positively charged in MeOH. For the fabrication of a uniform EPD layer, the cathode was placed in a porous alumina tube. The insides of the porous alumina tubes were filled with MeOH and the cathode did not make contact with the EPD bath. A 30 mm 200 gm 2 thick uniform LSCF powder coating was obtained by EPD at 100 V for 10 min. After sintering at 1500c C for 5 h, a 20 mm dense membrane was obtained.

Electrophoretic deposition: From traditional ceramics to nanotechnology

“…89 Moreover Chen et al 90 fabricated porous alumina membranes with uniform porous structure and suitable size for application in microfiltration. Huang and Yang 91 produced uniform and dense zeolite membranes on an alumina support and Negishi et al 92 deposited lanthanum cobaltite on a porous alumina tube by EPD and they were able to obtain dense membranes after a sintering step. Sun et al 93 deposited by EPD a welladherent ␥-Al 2 O 3 washcoat on metallic wire-mesh monoliths for applications in environmental catalysis and other industrial catalysis process (e.g., air pollution abatement devices and automotive emissions controls).…”

Inner Surface Coating of Non-Conductive Tubular Substrate Using Electrophoretic Deposition

“…The EPD cell setting for porous tubular substrate [3]. However, in this case, the electrical conductivity (5.9 s/cm) [6] of the Ppy coated glass slides seems adequate to maintain linearity in deposition even up to 10 min deposition time. Fig.4.…”

“…It can be used to apply deposits on flat, cylindrical or complex-shaped substrates. To obtain the layers on porous ceramic tubes, conductive materials such as Pt or stainless steel wire and cylindrical mesh as electrodes have been placed inside and outside of the porous tubes, respectively [4][5][6]. Though the coating of the outer surface of porous tubes using EPD technique has been widely reported, the coating the inner wall of the tubes is a challenge.…”

“…Glass slides were also used for the experiments to investigate the deposition characteristics. Ppy was coated on the substrates by chemical polymerization of pyrrole (Py) [6]. Ammonium peroxodisulfate ((NH 4 ) 2 S 2 O 8 ), an oxidant, and 2-6-naphthalenedisulfonic acid disodium salt (C 10 H 6 (SO 3 Na) 2 ), a doping agent, were firstly dissolved in water and cooled it down to 0 o C. The porous tubes, the outer surfaces of which were covered with a P.T.F.E.…”

Application of electrophoretic deposition for inner surface coating of porous ceramic tubes

“…A similar technique was used by Negishi et al to prepare a La 0.8 Sr 0.2 Co 0.8 Fe 0.2 O 3 − δ (LSCF) thin layer on the outer surface of a porous alumina tube[19].…”